Didit Face Match API

Overview

Compares two facial images to determine if they belong to the same person. Returns a similarity score (0-100).

Key constraints:

• Supported formats: JPEG, PNG, WebP, TIFF
• Maximum file size: 5MB per image
• If multiple faces in an image, the largest face is used for comparison
• Both user_image and ref_image are required

Capabilities: Similarity scoring, age estimation, gender detection, face bounding boxes, configurable decline threshold, optional image rotation for non-upright faces.

API Reference: https://docs.didit.me/standalone-apis/face-match Feature Guide: https://docs.didit.me/core-technology/face-match/overview

Authentication

All requests require x-api-key header. Get your key from Didit Business Console → API & Webhooks, or via programmatic registration (see below).

Getting Started (No Account Yet?)

If you don't have a Didit API key, create one in 2 API calls:

1. Register: POST https://apx.didit.me/auth/v2/programmatic/register/ with {"email": "you@gmail.com", "password": "MyStr0ng!Pass"}
2. Check email for a 6-character OTP code
3. Verify: POST https://apx.didit.me/auth/v2/programmatic/verify-email/ with {"email": "you@gmail.com", "code": "A3K9F2"} → response includes api_key

To add credits: GET /v3/billing/balance/ to check, POST /v3/billing/top-up/ with {"amount_in_dollars": 50} for a Stripe checkout link.

See the didit-verification-management skill for full platform management (workflows, sessions, users, billing).

Endpoint

POST https://verification.didit.me/v3/face-match/

Headers

Request Parameters (multipart/form-data)

Example

import requests

response = requests.post(
    "https://verification.didit.me/v3/face-match/",
    headers={"x-api-key": "YOUR_API_KEY"},
    files={
        "user_image": ("selfie.jpg", open("selfie.jpg", "rb"), "image/jpeg"),
        "ref_image": ("id_photo.jpg", open("id_photo.jpg", "rb"), "image/jpeg"),
    },
    data={"face_match_score_decline_threshold": "50"},
)

const formData = new FormData();
formData.append("user_image", selfieFile);
formData.append("ref_image", referenceFile);
formData.append("face_match_score_decline_threshold", "50");

const response = await fetch("https://verification.didit.me/v3/face-match/", {
  method: "POST",
  headers: { "x-api-key": "YOUR_API_KEY" },
  body: formData,
});

Response (200 OK)

{
  "request_id": "a1b2c3d4-...",
  "face_match": {
    "status": "Approved",
    "score": 80,
    "user_image": {
      "entities": [
        {"age": 27.63, "bbox": [40, 40, 100, 100], "confidence": 0.717, "gender": "male"}
      ],
      "best_angle": 0
    },
    "ref_image": {
      "entities": [
        {"age": 22.16, "bbox": [156, 234, 679, 898], "confidence": 0.717, "gender": "male"}
      ],
      "best_angle": 0
    },
    "warnings": []
  },
  "created_at": "2025-05-01T13:11:07.977806Z"
}

Status Values & Handling

Error Responses

Response Field Reference

Warning Tags

Security best practice: Only store the status and score. Minimize biometric image data on your servers. Image URLs (in workflow mode) expire after 60 minutes.

Score Interpretation

Utility Scripts

export DIDIT_API_KEY="your_api_key"

python scripts/match_faces.py selfie.jpg id_photo.jpg
python scripts/match_faces.py selfie.jpg id_photo.jpg --threshold 50 --rotate